2000 Ford Mustang AT base model v6 3.8 - radiator/heater core issue

wolfsmane

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So...after complete warm-up with fan off for five minutes...when you turned fan on high...did you get good heat for about 5-10 seconds before the heat faded to mediocre? No = blend air door problem. Yes = heater core is plugged, or flow is restricted, or persistent air pocket, or water pump is doing a poor job at low rpm. Does heater output temp improve a lot if you hold RPM about 3000 for 30 seconds?
The air temps at the vents were around 116F with no fan running and around 104F with the fan on high. I did not drive it, I have 4 ruptured discs in my lower back and this car kills me to drive it.

I wouldn't think that the water pump had an issue since it is cooling the engine as expected, never runs hot or over heats. The whole time I was checking the temps this morning was idling in the driveway.
 

Mobile Dan

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How does the Hot/Cold control seem to work? If that seems to be working 100% normal (not sticky, jamming, noisy)...then my best guess is... partially blocked heater core. If you say "But, But, But, Full flush and fill!" I'm just going to cross my arms and look you straight in the eyes and say nothing.
 

wolfsmane

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try dans idea, if you get heat at vents, @ 3 grand, air pocket.

Sorry about you being in pain, have you tried vacuum bleeding?
This messed my mind up a little bit, LOL! I have had several procedures done to help with the pain, but I have never
heard of vacuum bleeding for pain. Then, it dawned on me that you were talking about bleeding the radiator, LOL!!
 

wolfsmane

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How does the Hot/Cold control seem to work? If that seems to be working 100% normal (not sticky, jamming, noisy)...then my best guess is... partially blocked heater core. If you say "But, But, But, Full flush and fill!" I'm just going to cross my arms and look you straight in the eyes and say nothing.
Seems to be ok. I didn't hear any sticking or noise. I would not say anything like that with advise given to me by someone who
knows a hell of a lot more about this than I ever will.

When using the radiator flush, should I have left it in the system longer than the 2 days? Would it have caused any damage by
leaving it in the system for say a week or two?

I will try to bleed it again since that is the easiest thing to do.

Thanks for all of the replies and advise guys.
 

Mobile Dan

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It is possible that more junk came loose days or weeks after the "flush job" and that junk has some of the heater core tubes blocked.
 

wolfsmane

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So, I couldn't find the vacuum tool. They did have a pressure tool that I did rent and there are no leaks. As I had it under pressure, I release the bleeder that is right above the thermostat and got some air out of that.

Now, the one thing that I did catch, the radiator cap is supposed to be a 16 LB pressure cap. It wasn't, it was only an 11 LB pressure cap. I bought a new 16 LB cap and put that on it.

Car now seems like it heats up a little bit quicker now. So, I am going to let it go and keep an eye on it.

I appreciate every ones help here.
 
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